IOSR Journal of Electronics and Communication Engineering (IOSR-JECE) e-ISSN: 2278-2834,p- ISSN: 2278-8735. Volume 6, Issue 1 (May. - Jun. 2013), PP 07-10 www.iosrjournals.org www.iosrjournals.org 7 | Page Bandwidth enhancement of rectangular microstrip patch antenna using slots E.Sivakumar 1 , Srinivasa Rao O 2 , A.V.M.Manikandan 3 1(Dept of Electronics and Communication Engineering, SRM University, Chennai, India) 2(Communications Systems, SRM University, Chennai, India) 3(Dept of Electronics and Communication Engineering, SRM University, Chennai, India) Abstract : In this paper, a new design of rectangular microstrip patch antenna (RMPA) without slot, with slots and array is proposed and analyzed. The designed antenna has been simulated using HFSS software. The simulated results for return loss, radiation pattern and gain are presented and discussed. The bandwidth of proposed antenna is 2.4GHz-5.9GHz for VSWR(voltage standing wave ratio)<2 is achieved on the basis of <- 10dB return loss as an acceptable reference in wireless applications which cover worldwide interoperability for microwave access (WiMAX) and wireless local area network (WLAN) and other applications. Gain of 10dB is achieved for antenna array. Keywords- Array, Microstrip antenna, WLAN, WiMAX I. Introduction: There is a huge demand for the design of antennas which can operate over multiple bands due their vital role played in wireless communication systems. In order to satisfy the WLAN recommendations at 2.4/5.2/5.8 GHz operating bands and WiMAX standard at 2.5/3.5/5.5 GHz bands, microstrip patch antennas are preferred due to their extraordinary features. Microstrip patch antennas show some important features which are low profile, light weight, low cost, simplicity and inexpensive manufacturability using modern printed circuit technology, mechanical robustness when mounted on rigid surfaces, compatibility with Microwave Monolithic designs, etc. Selecting a particular patch shape and mode microstrip patch antennas are very versatile in terms of resonant frequency, polarization, pattern and impedance [1]. In [2], a unipolar printed couple-fed planar inverted-F antenna (PIFA) with a band-notching slit for WLAN/WiMAX applications has been demonstrated. In [3], a printed microstrip line-fed rhombus slot antenna with a pair of parasitic strips has been presented. In [4], a compact planar Ultra-Wideband (UWB) antenna with dual band-notched characteristics has been reported. In [5,6], many multiband antennas are presented but the reported designs lack achieving a dual band response with larger bandwidth to cover the whole WLAN/WiMAX bands. A multiband PIFA covering ten frequency bands has been proposed for personal wireless communication terminals in [7], but it covers only one band of WiMAX and two bands of WLAN with increased antenna size. The main drawback of this type of coupling feed is that the antenna is not sufficient to cover all frequency bands and the fabrication is difficult due to multiple layers. The microstrip antenna fed by Co-planar Waveguide (CPW) microstrip feed line has unique characteristics such as lower radiation leakage, wider bandwidth. The purpose of this paper is to present a new configuration of microstrip patch antenna array for WiMAX and WLAN applications. The antenna model consists of double L-slot microstrip patch antenna array. The radiating element used in this proposed antenna is copper and we prefer rectangular shape patches compared to other types since rectangular patches are the first and probably the most utilized patch conductor geometries. Initially single microstrip patch antenna is designed and the performance metrics such as radiation pattern, VSWR, return loss and gain are simulated. To increase the gain, a design of microstrip patch antenna array is also considered. The array consists of two single patches of antenna on the same substrate. The performance of a single patch antenna and double patch antenna array is compared. II. Antenna Design: The schematic configuration of the microstrip patch antenna is shown in Fig. 1. The dimensions of the radiating structures, patch width, and the feed point position are chosen according to the required frequency of operation. The radiating patch is fed by a 50Ω transmission line. The schematic configuration of the microstrip patch antenna with two slots is shown in the Fig2.The dimensions of two slots can be adjusted to radiate in the resonant frequency range. The dimensions of two slots are selected such that it should produce wider bandwidth and perfect impedance matching. Microstrip slot antennas are capable of producing omnidirectional radiation